Gene therapy could help treat Parkinson's
Critics: Success in monkeys could fail in humans
By Steve Sternberg - USA TODAY
http://www.usatoday.com/usatonline/20001027/2787819s.htm
October 27, 2000 -- Gene therapy in primates has succeeded in reversing
the nerve damage that occurs in Parkinson's disease, a study out today
says.
U.S. and Swiss researchers say the therapy relieved the tremors,
stiffness
and other motor symptoms caused by the disease.
"We can stop the progression of Parkinson's disease," says Jeffrey
Kordower, lead author of the study in today's Science. "We can stop the
motor deficits from emerging and from getting worse."
Researchers praise the study, but they caution that many potential
therapies don't make the leap from primates to humans.
"It's a tour de force," says Abraham Lieberman of the National Parkinson
Foundation in Miami Beach. "For the first time, they have targeted a
growth factor to an area of the brain in Parkinson's."
About 1.2 million people in the USA and Canada have Parkinson's
disease, a progressive breakdown of the brain region that affects motor
skills. This region, called the substantia nigra, is stocked with cells
that
produce dopamine, which governs smooth movement.
"We have fairly effective ways of treating (Parkinson's) symptoms, but
the
disease continues to progress," says Matthew Stern, director of the
University of Pennsylvania's Parkinson's Disease and Movement Disorders
Center. "But how can we prevent the damage from occurring?
"The next generation of therapies will be aimed at the disease process
itself. This research is the gateway."
Kordower of Rush Presbyterian-St. Luke's Medical Center in Chicago
and his team used a gene that makes a nerve-cell growth factor called
GDNF, which safeguards brain cells that die in Parkinson's disease. The
researchers inserted the gene into a special virus and injected it into
monkeys' brains.
Six injections increased dopamine production dramatically in eight
monkeys who were used to study the therapy's biological impact. The
researchers also injected the gene into 20 other monkeys, 90% of whose
dopamine-producing cells had been destroyed. The injections reversed the
brain cell destruction and improved their motor-skills performance to
"near
normal."
However, Lieberman cautions, "the monkey isn't an entirely faithful
model
of Parkinson's disease. Parkinson's evolves slowly, and the mechanism of
cell destruction may be different." In the study, researchers simulated
Parkinson's in monkeys by giving them a chemical that destroyed certain
brain cells.
Another obstacle is the challenge of delivering genes to the brain.
Human
gene therapy trials have been on hold since the death of a patient at
the
University of Pennsylvania last fall. "As long as the safety profile
looks
promising in experimental models," Stern says, "I think we should look
for
human trials in a few years."
© Copyright 2000 USA TODAY, a division of Gannett Co. Inc.
--
Judith Richards, London, Ontario, Canada
[log in to unmask]
Today’s Research...
Tomorrow’s Cure
